Since "The Scarlet Ibis" is told by a first-person narrator, we learn about the characters through his eyes. In telling the story, he tells us what the various characters said and did; he also gives us information directly from his understanding and interpretation of the characters. Most of all, in telling the story he reveals himself. We can assume that the narragor is reliable because many times he does not cast himself in an admirable light. He tells us, for instance, that there was a "knot of cruelty" within him, and he describes in detail at least two occasions when he tormented and abused his little brother--the first when he tried to make Doodle touch his own coffin, and the second when he abandoned him in the swamp during the storm.
Two scenes are especially effective in developing characterization. When Doodle buries the dead ibis, a little boy with the big shovel, his family stays inside the house and laughs at him through the window. These actions themselves reveal a great deal about the characters in a manner that is far more emotionally powerful than numerous paragraphs of exposition. Also, in the story's conclusion, the narrator holds his little brother's body and screams his name into the storm; he holds Doodle for a long time, trying to shield his body from the rain. The narrator is shown in this scene to be far more than proud and spiteful; he is capable also of deep love and suffering.